1. The Field of the Invention
The present invention relates to fluid delivery systems and, more specifically, diptube connectors for use in sterile fluid delivery systems.
2. Present State of the Art
Breakthroughs in the biological, pharmaceutical, and chemical fields are occurring at a rapid rate. As a result of the substantial research taking place and the many new applications introduced thereby, large amounts of sterile fluid materials are consumed. Cell culture media used in the biological field is one example of a sterile, fluid material. Scientists and technicians often require cell culture media for use in propagating cell and tissue cultures. Cell culture media is typically a solution of amino acids, electrolytes, serum, serum fractions, vitamins, and growth factors.
Practical use of sterile fluid materials requires that the fluids be dispensable in both an accurate and rapid fashion. Furthermore, the fluids must be dispensable in a fashion to maintain sterility. Even a slight breach of the sterile system can result in extensive costs resulting from contamination of large quantities of sterile material and the destruction of experiments or developments of cell cultures.
Dispensing of sterile fluids has been performed in a variety of different fashions. In one embodiment, a collapsible bag is used having an outlet tube attached thereto. The bag is supported while an exterior pump is used to draw the sterile fluid out through the outlet tube.
A diptube is used to withdraw the fluid from the bottom of the bag, thereby enabling removal of substantially all of the sterile fluid. The diptube comprises a tube having a first end fluid coupled with the outlet tube and a second end positioned at the bottom of the bag. Fluid exiting the bag enters the diptube at the bottom of the bag and then travels to the outlet tube from which it is eventually dispensed. The diptube is traditionally attached to the outlet tube using a multi-barb adapter. For example, depicted in FIG. 1 is one embodiment of a prior art fluid delivery system 1. Fluid delivery system 1 comprises a bag 2 having an outlet tube 3 projecting therefrom. Attached to the end of outlet tube 3 is a multi-barb adapter 4. Adapter 4 has a first end 5, an opposing second end 6, and a passageway 7 extending therebetween. Formed at first end 5 of adapter 4 is a small hose barb 8. Spaced back from small hose barb 8 is a large hose barb 9. A similar large hose barb 10 is positioned at second end 6.
During assembly, small hose barb 8 is received within the first end of a diptube 11 while large hose barb 9 is received within the end of outlet tube 3. The opposing large hose barb 10 is received within the end of a delivery tube 11. In this configuration, fluid travels from diptube 11 through the passageway in adapter 4, and out through delivery tube 11.
Although functional, use of conventional multi-barb adapters, such as adapter 4, has produced contamination problems for the sterile system. Such adapters are typically manufactured from plastic using an injection molding process. Because of the required multiple barbs, and particularly the multiple barbs at one end thereof, the molds for the adapter must necessarily open along the longitudinally axis of the adapter. The molds are prevented from separating along a plane transverse to the longitudinal axis since the barbs would catch within the molds. As a result of the molds opening along the longitudinal axis, seam lines or ridges are formed longitudinally across each of the barbs. These seam lines create minute passageways between the surface of the barb and the corresponding tube received over the barb. Such passageways enable microscopic contaminates to pass from the exterior to the interior of the sterile system, thereby contaminating the system.
Another problem with multi-barb adapters is that they are designed to connect with select sizes of hoses and diptubes. During manufacture, however, it is desirable to produce fluid delivery systems having different tube sizes to accommodate different flow rates. To accommodate different tube sizes, different adapters of different barb sizes must be used. Accordingly, a variety of different sized adapters must be manufactured and inventoried. Furthermore, in some designs it is desirable not to have a diptube.